SMTP Rules for Firewall

General SMTP rule for Forti

create firewall objecty for Exchange server
Name it Exchange and assign it the private IP of the exchange server

create 3 policies (the third will probably already exist)

1. This rule says: "let all traffic for Exchange server using SMTP go out wan1"
Internal -> wan1
Source interface: internal
Source Addres: Exchange (Firewall object created previously)
Dest Interface: wan1
Dest address: all
Service: SMTP
Action: ACCEPT

2. This rule says: "stop all traffic using SMTP from going out wan1"
Internal -> wan1
Source interface: internal
Source Addres: all
Dest Interface: wan1
Dest address: all
Service: SMTP
Action: DENY

3. catch all rule that allows all traffic to flow (except SMTP)
Internal -> wan1
Source interface: internal
Source Addres: all
Dest Interface: wan1
Dest address: all
Service: all
Action: ALL